1. Field
The following description relates to a three dimensional (3-D) image display apparatus, and more particularly, to a 3-D image display apparatus with an expanded viewing zone.
2. Description of the Related Art
Three dimensional (3-D) image display apparatuses are widely used in a variety of fields such as medical imaging, games, advertisements, education, and military applications. For displaying a 3-D image, methods such as a holography method or a stereoscopy method have been studied. Although the holography method is an exceptional 3-D image display method, the holography method generally requires a coherent light source and presents difficulties in recording and reproducing a large object located at a far distance.
The stereoscopy method generates a sense of depth by providing two separate two-dimensional (2-D) images having binocular parallax to both eyes of a viewer. Thus method using two plane images may be relatively simply implemented. The stereoscopy method may be implemented by methods such as a glasses type method including an auxiliary unit for seeing separated images for both eyes, or an autostereoscopy method of forming a viewing zone by directly separating an image formed by a display. The autostereoscopy method is generally preferred to the glasses type method, which is inconvenient simply because glasses are required. The autostereoscopy method is typically implemented with a parallax barrier method or a lenticular lens method.
The stereoscopy method may be implemented in a system by an arrangement of only optical components. However, since left and right images are formed at one screen, resolution may be reduced by half or more when compared to viewing a 2-D image on the screen. Also, since a viewing zone is limited according to a viewpoint, it may be inconvenient for a viewer to fix their position to the viewpoint when viewing a 3-D image. For example, when an image with only two viewpoints is provided, a range for a viewer to observe the 3-D image is very limited. If the viewer moves his or her head, left and right images may be reversed; thus, the viewer may be inconvenienced when watching a 3-D image. In addition, when the number of viewpoints is increased in order to expand the viewing zone, resolution may be reduced accordingly.